Abstract
Hydrogenated metal borides have attracted much attention due to their potential high-temperature superconductivity.Here,we propose a new strategy for hydrogen intercalation tuning the stability and superconductivity of the boron honeycomb sublattice,and predict an unprecedented layered compound Na2B2H,which hosts excellent superconductivity.Strikingly,the super-conducting transition temperature(Tc)of Na2B2H reaches 42 K at ambient pressure.The Tc value can be further increase to 63 K under 5％biaxial tensile strain.The excellent superconductivity originates from the strong electron-phonon coupling between theσ-bonding bands near the Fermi level and the B-B stretching optical E'modes.The interstitial electron localization and crystal orbitals of the H-intercalated Na ion layer well match the boron honeycomb lattice and act as a chemical template to stabilize the B layer.Furthermore,the introduction of hydrogen tuned the Fermi level,and the coupling vibration of Na and H ions effectively enhanced the dynamic stability of the structure.Na2B2H represents a new family of layered high-temperature superconductors,and the strategy of stabilizing the honeycomb boron sublattice via chemical template hosts great potential for application to more layered compounds.
万方数据